telephoto

We are all (hopefully) aware that we can be watched while we’re online. Our clicks are all trackable to some extent, whether it’s our country’s government or an advertiser. What isn’t as obvious, though, is that it’s just as easy to track our movements in real life. [Saulius] was able to prove this concept by using optical character recognition to track the license plate numbers of passing cars half a kilometer away.

To achieve such long distances (and still have clear and reliable data to work with) [Saulius] paired a 70-300 mm telephoto lens with a compact USB camera. All of the gear was set up on an overpass and the camera was aimed at cars coming around a corner of a highway. As soon as the cars enter the frame, the USB camera feeds the information to a laptop running openALPR which is able to process and record license plate data.

The build is pretty impressive, but [Saulius] notes that it isn’t the ideal setup for processing a large amount of information at once because of the demands made on the laptop. With this equipment, monitoring a parking lot would be a more feasible situation. Still, with even this level of capability available to anyone with the cash, imagine what someone could do with the resources of a national government. They might even have long distance laser night vision!

It may seem trivial at first, but the effect [Dan] gets when using binoculars as a telephoto lens is surprising. The images are well in focus with great colors. This technique not only brings your subject mater closer but also provides a depth-of-focus feature not normally available on simple cameras or camera phones.

The proof is in the example footage found after the break, but you’ll also find a video tutorial detailing the build. [Dan] already had the expensive components are a pair of mini binoculars and a Kodak Zx3 pocket camcorder. The camcorder is the same form factor as a smart phone so using different hardware will be a breeze. He started off by building a prototype out of paper. Basically it’s a bracket that properly aligns the camera with one lens of the binoculars. Once he had everything lined up he transferred his measurements to some sheet metal. The bracket for the binoculars is attached to the one for the camera using bolts and wing nuts to make it adjustable. One important part of the design is to gut a hole for access to the binocular focus wheel.